Penske's first Cup? Surely that's wrong, they probably thought over their coffee. Hasn't Roger Penske won a zillion of everything meaningful in American motorsports? Hasn't he won loads of Indianapolis 500s and all those stock-car races and a bunch of Daytona 500s and Sprint Cups and sports-car events and whatever else? Certainly his NASCAR teams could not have been this good for this long, yet not won a Sprint Cup until this year with a kid from Rochester Hills, Mich., behind the wheel?

Believe it.

Penske is America's—maybe even the world's—most successful and recognizable race-team owner. His organization's resume features 15 Indy 500 victories, a dozen IndyCar season championships and 165 IndyCar race wins. Penske Racing has won 91 NASCAR Sprint Cup poles and 73 races, including the 2008 Daytona 500 with Ryan Newman. Penske's Nationwide Series teams have won 20 poles and 26 races, and the 2010 Nationwide championship with Keselowski. Penske Racing also has won its share of major domestic and international sports-car races.

But Penske had never won a NASCAR Cup until Keselowski finished 15th in the season-ending 400-mile race at Homestead-Miami Speedway on Nov. 18. That's exactly where Keselowski needed to finish to guarantee that, even if Jimmie Johnson won the race and earned maximum points, it wouldn't be enough to deny Keselowski the Cup. Johnson looked poised to steal his sixth title in seven years until a botched late-race pit stop and an unrelated mechanical failure a few laps later sent him to the garage and out of the race.

Nobody perched atop Penske Racing's pit box or on the ground celebrated early. Not with Penske watching from the spotters' stand. Even with 22 laps remaining, when NASCAR confirmed that Johnson was eliminated mathematically from the chase, the crew waited for the checkered flag. (Jeff Gordon, cautiously running on fumes down the stretch, won the race with Clint Bowyer finishing second, and Newman, Kyle Busch and Greg Biffle rounding out the top five.

It was his second win of the year, his first at Homestead and the 87th of his career. Johnson finished 36th, sidelined with 43 laps remaining by a rear-gear failure.)

The celebration that followed—and which may still be raging somewhere—was 40 years in the making.

Penske dabbled in NASCAR with very minor success (six wins in 104 starts) between 1972 and 1980.

He fielded limited-schedule AMC Matadors and Mercuries for Dave Marcis, Mark Donohue, Bobby and Donnie Allison, Gary Bettenhausen, George Follmer, Neil Bonnett and (for two races in 1980) a full-of-himself young Midwesterner named Rusty Wallace. Only Bobby Allison (five) and Donohue (one) won races for Penske.

So he left NASCAR for 10 years, returning in 1991 with Wallace, by now a proven winner and the 1989 NASCAR champion with owner Raymond Beadle.

It is worth noting that Penske's organization won five Indy 500s and six championships during those 10 years without NASCAR on its plate. Beginning in '91, Penske fielded a single-car Cup team with Wallace for seven seasons before adding a second car for Jeremy Mayfield for the 1998-2000 seasons. He added Newman to the mix in 2001, then dropped Mayfield and kept only Newman and Wallace for the 2002-2004 seasons.

Inexplicably, Penske added Travis Kvapil to the Newman-Wallace lineup in 2005, Wallace's last season in Cup. Penske replaced the TV-bound Wallace with Kurt Busch for two years before adding a third car in 2008 for IndyCar star Sam Hornish Jr. When Newman left after 2009, Penske kept Busch and Hornish in place and added—again, inexplicably—David Stremme for one year.

Keselowski replaced Stremme on Penske's three-car team in 2010, and then ran 2011 with Busch as his only teammate. He opened 2012 with A.J. Allmendinger as his only teammate after Penske booted Busch a year ago. Keselowski found himself again teaming with Hornish when Allmendinger was fired in August after infamously failing a NASCAR drug test.

And there he stood on a sultry Sunday night in south Florida, fireworks exploding all around him, enjoying enough hand-shaking and back-slapping and congratulations to last a lifetime. Penske—“The Captain”—had finished top-10 in Sprint Cup points 19 times dating to Bobby Allison in 1976, but now he finally embraced the only number he ever really wanted for his NASCAR team.

We sat down with Penske and talked about the long and often difficult slog to the very top of stock-car racing.

Autoweek: Of all the great drivers you've had from any series—Mark Donohue, Rick Mears, Helio Castroneves, Rusty Wallace, Danny Sullivan, Emerson Fittipaldi, the Unsers—which one does Brad most remind you of?

Roger Penske: He's a lot like Rick Mears. He's understated, but he digs down deep when it's time to make things happen. He has the same consistency as Rick had and obviously is a winner. He's in Rick's category, which is a pretty special class as far as I'm concerned.

AW: How has he changed since he came to you? What do you see now that you don't remember seeing earlier, when he first started driving for you as Rusty Wallace's replacement?

RP: The most important thing is that he's gained respect in the garage area. Early on, Brad was rough; he was bumping people; there were the incidents with Carl Edwards and other people. But he's emerged and learned just like a lot of great drivers have learned after going through a rough patch. It's amazing [how quickly] he's gone from where he was when he first started with us to where he is today: smooth, understanding the car and being a winner. He's done all that in just 36 months with us.

AW: Why did you come back to NASCAR after your somewhat mediocre results with a number of drivers in the 1970s and 1980?

RP: I'm a goal-oriented person, and there's no question that a Sprint Cup championship is something everybody in racing wants. We've spread ourselves through many series with great success but never had quite gotten to the top in Cup. It's not about money and what you can buy; it's about the people, the human capital we've put together. The business has changed to being more technical now, and that's a little more in our bailiwick.

AW: Are you surprised it took this long for the first Cup title? Wallace said after you guys were close in 1993, 1994 and 1995 he thought Penske Racing would certainly win several Cups. But it took a kid in only his third full season to finally do it for you.

RP: We've been close and have won a lot of races, but we haven't had as many [championship] chances because we haven't had that many [total team] starts. A multitude of things have made a difference. When you look at the great teams we've competed against, there's been super competition. And people maybe haven't thought about us going to two cars, but the two-car team concept has helped us from an engineering standpoint.

AW: Brad and crew chief Paul Wolfe seemed immune to the pressure of being in position to win the championship over a five-time champion like Jimmie Johnson. Were they really that calm going into the final race?

RP: Brad trained over the past 13 or 14 weeks to get there. He's a calculating driver, smart and a student of the sport. His windshield is much wider than many other drivers' [because] he sees what's going on all around him. He rehearsed with Paul what things could happen during the race. He's a great athlete and a great driver, a thinking-man's driver. That's very important in today's sport.

AW: Did you give him any last-minute advice based on what happened in the IndyCar season finale, when Will Power spun early and probably cost you guys the title? Was there anything you tried to teach him from that experience?

RP: We didn't even talk about that. It wasn't a factor. We were here at a mile-and-a half track, where Brad has always excelled. Will is the best on road courses, and he's trying to get his feet under him on ovals. They were two different circumstances and never were a discussion factor at Penske Racing.

AW: Earlier in the weekend before the race was run, would you have agreed to trade a win in next year's Indy 500 for winning this year's Sprint Cup?

RP: That's a hard one. Obviously, this came first because it's something we'd never achieved as a company and a team. That's the most important thing I've had to deal with. But, yes, if I'd absolutely known for certain on Saturday or Sunday morning that we could have the Sprint Cup, I think I would have agreed to give up next year's 500.

AW: Your team moves to Ford next year as Dodge exits Cup, which is a bit strange considering you just won the championship together . . .

RP: Dodge has been a great partner. We've been with them for 10 years. The support they've given us over these last 12 months has been doubled up. We had a great relationship. We represent them in the retail auto network, so we're a big supporter of their products. It's one of those things where timing, budgets and other things really made the difference. I hope they'll be back in 2014 and maybe our results might help accelerate them to get back in the sport on a full-time basis.